JP4743845B2 - Hydrophobic positively charged silica fine powder, method for producing the same, and toner for developing electrostatic latent image to which it is added as an external additive - Google Patents
Hydrophobic positively charged silica fine powder, method for producing the same, and toner for developing electrostatic latent image to which it is added as an external additive Download PDFInfo
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本発明は、疎水性正帯電シリカ微粉末、その製造方法および上記疎水性正帯電シリカ微粉末を外添剤として添加した静電潜像現像用トナーに関するものである。上記疎水性正帯電シリカ微粉末は、複写機やプリンターなどの複写画像を形成するための静電潜像現像用トナーの外添剤として有用であって、該疎水性正帯電シリカ微粉末を外添剤として添加することにより、流動性が優れ、かつ帯電性能の環境安定性が良好で、鮮鋭性の高い画像が安定して得られる静電潜像現像用トナーを提供することができる。 The present invention relates to a hydrophobic positively charged silica fine powder, a method for producing the same, and a toner for developing an electrostatic latent image to which the hydrophobic positively charged silica fine powder is added as an external additive. The hydrophobic positively charged silica fine powder is useful as an external additive for toner for developing an electrostatic latent image for forming a copy image of a copying machine or a printer. By adding it as an additive, it is possible to provide a toner for developing an electrostatic latent image, which has excellent fluidity, good environmental stability of charging performance, and can stably obtain a sharp image.
近年、複写機やプリンターなどにより得られる静電画像の高精細、高画質化への要求が市場で高まっており、トナーの小粒径化が進んでいる。また、トナーの結着樹脂としてポリエステル系樹脂を用いることにより高画質化を達成しようとすることも行われている。
しかし、ポリエステル系樹脂を用いると湿度の影響を受けやすくなり、低湿度下においては帯電量が高くなりすぎて画像欠陥が生じやすくなり、逆に高湿度下においては帯電量が不足して現像性が悪化し、鮮鋭性の高い画像が得られなくなるという問題があった。
In recent years, demands for high definition and high image quality of electrostatic images obtained by copying machines, printers, and the like have increased in the market, and toner particle size has been reduced. In addition, attempts have been made to achieve high image quality by using a polyester resin as a binder resin for toner.
However, if polyester resin is used, it tends to be affected by humidity, and the charge amount becomes too high at low humidity and image defects are likely to occur. As a result, the sharpness of the image could not be obtained.
また、複写機やプリンターなどに組み込まれる感光体として、廃棄の際に環境に優しい有機半導体を使用し、耐久性に優れた負極性有機感光体を使用するケースが増加している。 In addition, as a photoconductor incorporated in a copying machine, a printer or the like, there are an increasing number of cases where an organic semiconductor that is environmentally friendly at the time of disposal is used and a negative organic photoconductor excellent in durability is used.
この負極性有機感光体には、負極性コロナ放電を利用した負極性トナーが使用されるが、負極性コロナ放電はオゾンを発生しやすく、そのため、使用環境が悪化されるという問題がある。そこで、使用環境の悪化を防止するという観点から、最近は、正極性トナーを使用した正極性感光体の使用が増加している。 For this negative organic photoconductor, a negative toner using negative corona discharge is used, but negative corona discharge tends to generate ozone, and there is a problem that the use environment is deteriorated. Thus, from the viewpoint of preventing deterioration of the use environment, the use of a positive photosensitive member using a positive toner has been increasing recently.
また、従来から、トナーに対して流動性付与や帯電性能付与、あるいはクリーニング性向上などの目的で、シリカや酸化チタンなどの無機酸化物粉体を外添することが行われているが、シリカを外添したトナーは、流動性は優れているものの、帯電性能の環境安定性が充分でないという問題があり、また、酸化チタンを外添したトナーは、帯電性能の環境安定性は優れているものの、流動性が充分でないという問題を有している。 Conventionally, inorganic oxide powders such as silica and titanium oxide have been externally added to the toner for the purpose of imparting fluidity, imparting charging performance, or improving cleaning properties. Although the toner added externally has excellent fluidity, there is a problem that the environmental stability of charging performance is not sufficient, and the toner externally added with titanium oxide has excellent environmental stability of charging performance. However, it has a problem of insufficient fluidity.
前記のように、正極性感光体には正極性トナーが使用されるが、正極性トナーとするためには、外添するシリカや酸化チタンなどの無機酸化物粉体も、正帯電性（正極性）であることが必要である。 As described above, a positive toner is used for the positive photosensitive member. However, in order to obtain a positive toner, an inorganic oxide powder such as silica or titanium oxide to be externally added is also positively charged (positive electrode). Sex).
そのため、元来負極性であるシリカを正極性トナーに外添しようとした場合、シリカを正帯電性にする必要があるが、そのような負極性のシリカを正帯電性にする方法としてはアミノシランでシリカ表面を処理する方法が提案されている（特許文献１）。 Therefore, when externally adding silica having negative polarity to the positive toner, it is necessary to make the silica positively charged. As a method for making such negative silica positively charged, aminosilane can be used. A method of treating the silica surface with the method has been proposed (Patent Document 1).
しかし、この方法による場合、確かに正帯電性のシリカが得られるものの、アミノシランが親水性であるため、湿度に対する耐性が悪く、そのため、帯電性能の環境変化が大きくなり、それによって、帯電性能が低下するという問題があった。 However, according to this method, although positively charged silica can be obtained, the aminosilane is hydrophilic, so the resistance to humidity is poor. Therefore, the environmental change of the charging performance is increased, thereby increasing the charging performance. There was a problem of lowering.
そこで、上記のような問題を解消するため、シリカをアミノシランと疎水化剤の両方で処理する方法が提案されている（特許文献２〜４）。 Therefore, in order to solve the above problems, methods for treating silica with both aminosilane and a hydrophobizing agent have been proposed (Patent Documents 2 to 4).
しかし、これらの方法による場合は、シリカ表面の疎水性が向上し、湿度に対する耐性も向上するものの、元来のシリカの強い親水性を完全に消し去ることができず、帯電性能の環境安定性が充分でないという問題があった。 However, when these methods are used, the hydrophobicity of the silica surface is improved and the resistance to humidity is improved, but the strong hydrophilicity of the original silica cannot be completely removed, and the environmental stability of the charging performance. There was a problem that was not enough.
そのため、シリカ、酸化チタンなどの数種類の外添剤を併用して流動性と帯電性能の環境安定性を調整したり、あるいは、トナー用樹脂の改良などによって流動性と帯電性能の環境安定性を調整しているのが現状であり、そのため、流動性が優れ、かつ帯電性能の環境安定性が良好な疎水性正帯電シリカの出現が待たれている。
本発明は、前記のような従来技術の問題点を解決し、流動性が優れ、かつ帯電性能の環境安定性が良好で、鮮鋭性の高い画像が安定して得られる静電潜像現像用トナーを得るのに適した疎水性正帯電シリカ微粉末を提供し、また、その疎水性正帯電シリカ微粉末を外添剤として添加することによって上記特性を有する静電潜像現像用トナーを提供することを目的とする。 The present invention solves the problems of the prior art as described above, and for developing an electrostatic latent image in which fluidity is excellent, environmental stability of charging performance is good, and a sharp image is stably obtained. Provided is a hydrophobic positively charged silica fine powder suitable for obtaining a toner, and an electrostatic latent image developing toner having the above characteristics by adding the hydrophobic positively charged silica fine powder as an external additive The purpose is to do.
本発明者は、上記課題を解決するため種々研究を重ねた結果、シリカをアミノ基を含有するケイ素化合物（以下、簡略化して、「アミノ基含有ケイ素化合物」という場合がある）とアミノ基を含有しないケイ素化合物（以下、簡略化して、「アミノ基非含有ケイ素化合物」という場合がある）との２種のケイ素化合物で疎水化処理するとともに、疎水化処理前のシリカのＢＥＴ比表面積とシリカに対する２種のケイ素化合物の添加量に関して、ある特定の関係を満たさせることにより、流動性が優れ、かつ帯電性能の環境安定性が良好で、鮮鋭性の高い画像が安定して得られる静電潜像現像用トナーを提供することができる疎水性正帯電シリカ微粉末が得られることを見出し、それに基づいて本発明を完成した。 The present inventor has conducted various studies to solve the above problems, and as a result, silica has a silicon compound containing an amino group (hereinafter sometimes referred to as “amino group-containing silicon compound”) and an amino group. Hydrophobic treatment with two types of silicon compounds with silicon compounds that do not contain (hereinafter sometimes referred to as “amino group-free silicon compounds”), and BET specific surface area of silica before hydrophobization treatment and silica By satisfying a specific relationship with respect to the addition amount of the two types of silicon compounds with respect to the electrostatic capacity, the fluidity is excellent, the environmental stability of the charging performance is good, and a static image with high sharpness can be stably obtained. The present inventors have found that a hydrophobic positively charged silica fine powder capable of providing a latent image developing toner can be obtained, and the present invention has been completed based on this.
すなわち、本発明は、２種のケイ素化合物で疎水化処理された疎水性正帯電シリカ微粉末であって、２種のケイ素化合物のうち１種がアミノ基を含有するケイ素化合物であり、他の１種がアミノ基を含有しないケイ素化合物であって、疎水化処理前のシリカのＢＥＴ比表面積をＳ（ｍ２／ｇ）とし、このシリカに対するアミノ基を含有するケイ素化合物の添加量をＡ（質量％）とし、アミノ基を含有しないケイ素化合物の添加量をＢ（質量％）とするとき、上記Ｓ、Ａ、Ｂに関して、（Ａ＋Ｂ）／Ｓの数値（Ｍ）が０．１０≦Ｍ≦０．３０で、かつ０．５≦Ａ／Ｂ≦２．０の関係を満たすことを特徴とする疎水性正帯電シリカ微粉末と、その疎水性正帯電シリカ微粉末の製造方法に関するものであり、さらには、その疎水性正帯電シリカ微粉末を外添剤として添加したことを特徴とする静電潜像現像用トナーに関するものである。 That is, the present invention is a hydrophobic positively charged silica fine powder hydrophobized with two types of silicon compounds, one of the two types of silicon compounds being a silicon compound containing an amino group, One type is a silicon compound that does not contain an amino group, and the BET specific surface area of the silica before hydrophobization treatment is S (m 2 / g), and the addition amount of the silicon compound containing an amino group to this silica is A ( Mass%), and the addition amount of the silicon compound containing no amino group is B (mass%), the numerical value (M) of (A + B) / S is 0.10 ≦ M ≦ The present invention relates to a hydrophobic positively charged silica fine powder characterized by satisfying a relationship of 0.30 and 0.5 ≦ A / B ≦ 2.0, and a method for producing the hydrophobic positively charged silica fine powder. In addition, its hydrophobic positively charged silica fine It relates a toner for developing electrostatic latent images which is characterized by the addition of end as an external additive.
本発明によれば、複写機やプリンターなどの複写画像を形成するための静電潜像現像用トナーの外添剤として有用な疎水性正帯電シリカ微粉末を提供することができる。 ADVANTAGE OF THE INVENTION According to this invention, the hydrophobic positively charged silica fine powder useful as an external additive of the electrostatic latent image developing toner for forming copy images, such as a copying machine and a printer, can be provided.
そして、上記疎水性正帯電シリカ微粉末を外添剤として添加することにより、流動性が優れ、かつ帯電性能の環境安定性が良好で、鮮鋭性の高い画像が安定して得られる静電潜像現像用トナーを提供することができる。 Further, by adding the above-mentioned hydrophobic positively charged silica fine powder as an external additive, an electrostatic latent image that has excellent fluidity and good environmental stability of charging performance, and can stably obtain a sharp image. An image developing toner can be provided.
本発明の疎水性正帯電シリカ微粉末は、その代表的用途が静電潜像現像用トナーの外添剤であるが、その流動性が優れ、かつ帯電性能の環境安定性能が良好であるという特性を利用して、粉体塗料、樹脂用添加剤などに利用することができる。 The hydrophobic positively charged silica fine powder of the present invention is representatively used as an external additive for a toner for developing an electrostatic latent image, but its fluidity is excellent and the environmental stability performance of the charging performance is also good. By utilizing the characteristics, it can be used for powder coatings, additives for resins, and the like.
本発明の疎水性正帯電シリカ微粉末が、流動性が優れ、かつ帯電性能の環境安定性が良好である理由、および、本発明の疎水性正帯電シリカ微粉末を外添剤として添加した静電潜像現像用トナーが、流動性が優れ、かつ帯電性能の環境安定性が良好で、鮮鋭性の高い画像が安定して得られるようになる理由は、以下の「発明を実施するための最良の形態」の項において、本発明の疎水性正帯電シリカ微粉末を構成する材料などの説明と共に説明する。 The reason why the hydrophobic positively charged silica fine powder of the present invention is excellent in fluidity and the environmental stability of the charging performance is excellent, and the hydrophobic positively charged silica fine powder of the present invention is added as an external additive. The reason why the toner for developing an electrostatic latent image has excellent fluidity and environmental stability of charging performance and a sharp image can be stably obtained is as follows. In the section of “Best Mode”, the material constituting the hydrophobic positively charged silica fine powder of the present invention will be described together with the description.
本発明の疎水性正帯電シリカ微粉末は、２種のケイ素化合物で疎水化処理されているが、正帯電性を付与するためには、そのうちの１種はアミノ基を含有するケイ素化合物であることが必要である。 The hydrophobic positively-charged silica fine powder of the present invention is hydrophobized with two types of silicon compounds, but in order to impart positive chargeability, one of them is a silicon compound containing an amino group. It is necessary.
このアミノ基を含有するケイ素化合物としては、特に特定のものに制約されることなく種々のものを使用できるが、このアミノ基を含有するケイ素化合物としては、例えば、アミノ基含有シランカップリング剤、アミノ変性シリコーンオイル、第四級アンモニウム塩型シランなどを用いることができる。それらの中でも、正帯電付与能力と流動性との観点から、アミノ基含有シランカップリング剤が特に好ましい。このアミノ基含有シランカップリング剤の具体例としては、例えば、Ｎ−２（アミノエチル）３−アミノプロピルメチルジメトキシシラン、Ｎ−２（アミノエチル）３−アミノプロピルトリメトキシシラン、３−アミノプロピルトリメトキシシラン、３−アミノプロピルトリエトキシシラン、Ｎ−フェニル−３−アミノプロピルトリエトキシシランなどが挙げられるが、それらの中でも、帯電性能の環境安定性の向上効果が優れていることから、３−アミノプロピルトリエトキシシランが特に好ましい。 As the silicon compound containing an amino group, various compounds can be used without any particular restriction. Examples of the silicon compound containing an amino group include an amino group-containing silane coupling agent, Amino-modified silicone oil, quaternary ammonium salt type silane and the like can be used. Among these, an amino group-containing silane coupling agent is particularly preferable from the viewpoint of positive charge imparting ability and fluidity. Specific examples of the amino group-containing silane coupling agent include, for example, N-2 (aminoethyl) 3-aminopropylmethyldimethoxysilane, N-2 (aminoethyl) 3-aminopropyltrimethoxysilane, 3-aminopropyl. Examples include trimethoxysilane, 3-aminopropyltriethoxysilane, N-phenyl-3-aminopropyltriethoxysilane, and the like. Among them, the effect of improving the environmental stability of charging performance is excellent. -Aminopropyltriethoxysilane is particularly preferred.
また、上記アミノ基を含有するケイ素化合物に対して、アミノ基を含有しないケイ素化合物としては、アミノ基を含まず疎水性を発現するものであれば、特に制約を受けることなく種々のものを用いることができるが、帯電性能の環境安定性や流動性の観点から、例えば、アルコキシシラン、シランカップリング剤、シラザン、シリコーンオイル、シリコーンレジンなどが好ましく、特にアルコキシシラン、シリコーンオイル、シリコーンレジンが好ましい。上記アルコキシシランとしては、例えば、イソブチルトリメトキシシラン、オクチルトリエトキシシラン、トリフルオロプロピルトリメトキシシランなどが挙げられ、シリコーンオイルとしては、例えば、ジメチルポリシロキサン、メチルハイドロジェンポリシロキサンなどのストレートシリコーンオイルやエポキシ変性シリコーンオイル、フッ素変性シリコーンオイルなどの変性シリコーンオイルなどが挙げられ、シリコーンレジンとしては、例えば、トリメチルシロキシケイ酸が挙げられる。 In addition to the amino group-containing silicon compound, as the silicon compound not containing an amino group, various compounds can be used without any particular limitation as long as they do not contain an amino group and develop hydrophobicity. However, from the viewpoint of environmental stability and fluidity of charging performance, for example, alkoxysilane, silane coupling agent, silazane, silicone oil, silicone resin and the like are preferable, and alkoxysilane, silicone oil and silicone resin are particularly preferable. . Examples of the alkoxysilane include isobutyltrimethoxysilane, octyltriethoxysilane, and trifluoropropyltrimethoxysilane. Examples of the silicone oil include straight silicone oil such as dimethylpolysiloxane and methylhydrogenpolysiloxane. And modified silicone oils such as epoxy-modified silicone oil and fluorine-modified silicone oil. Examples of the silicone resin include trimethylsiloxysilicic acid.
上記２種のケイ素化合物のシリカに対する添加量（処理量）は、帯電性能の環境安定性を満足させる観点から、以下の関係を満たすことが必要である。 From the viewpoint of satisfying the environmental stability of the charging performance, the addition amount (treatment amount) of the two types of silicon compounds to silica needs to satisfy the following relationship.
すなわち、疎水化処理前のシリカのＢＥＴ比表面積をＳ（ｍ２／g）とし、このシリカに対するアミノ基を含有するケイ素化合物の添加量をＡ（質量％）（シリカ１００質量部に対してアミノ基を含有するケイ素化合物がＡ質量部）とし、アミノ基を含有しないケイ素化合物の添加量をＢ（質量％）（シリカ１００質量部に対してアミノ基を含有しないケイ素化合物がＢ質量部）とするとき、上記Ｓ、Ａ、Ｂに関して、（Ａ＋Ｂ）／Ｓの数値（Ｍ）が０．１０≦Ｍ≦０．３０であり、かつ、０．５≦Ａ／Ｂ≦２．０の関係を満たすことが必要であり、特に０．１０≦Ｍ≦０．２２で、かつ、Ａ／Ｂ＝１．０であることが好ましい。 That is, the BET specific surface area of the silica before the hydrophobization treatment is S (m 2 / g), and the addition amount of the silicon compound containing an amino group with respect to this silica is A (mass%) (amino based on 100 parts by mass of silica). The silicon compound containing a group is A part by mass), and the addition amount of the silicon compound not containing an amino group is B (mass%) (the silicon compound containing no amino group is 100 parts by mass of silica and B part by mass). When S, A, and B, the numerical value (M) of (A + B) / S is 0.10 ≦ M ≦ 0.30 and 0.5 ≦ A / B ≦ 2.0. It is necessary to satisfy, and it is particularly preferable that 0.10 ≦ M ≦ 0.22 and A / B = 1.0.
上記数値（Ｍ）は、シリカ表面に対する２種のケイ素化合物の被覆度合いであり、Ｍ＜０．１０の場合には、ケイ素化合物の被覆度が不足していて、帯電性能の環境安定性が悪くなる。また、Ｍ＞０．３０の場合には、ケイ素化合物の被覆度としては充分であるが、逆に被覆過剰となり、ケイ素化合物同士が結合して自己縮合物が生じやすくなるため、疎水化処理が不均一になりやすい。そのため、帯電性能の環境安定性が悪化したり、シリカの凝集力が強くなって流動性が低下するなどの問題がある。 The above numerical value (M) is the degree of coverage of two types of silicon compounds on the silica surface. When M <0.10, the degree of coverage of the silicon compound is insufficient and the environmental stability of the charging performance is poor. Become. Further, when M> 0.30, the coverage of the silicon compound is sufficient, but conversely, the coating becomes excessive, and the silicon compounds are easily bonded to each other, so that a self-condensate is easily formed. It tends to be uneven. For this reason, there are problems such as deterioration in the environmental stability of the charging performance, and a decrease in fluidity due to the strong cohesive force of silica.
本発明では、さらに、上記Ａ、Ｂに関して、０．５≦Ａ／Ｂ≦２．０の関係を満たすことが必要である。このＡ／Ｂはシリカを被覆するアミノ基を含有するケイ素化合物とアミノ基を含有しないケイ素化合物との比率を示し、Ａ／Ｂ＜０．５の場合は、アミノ基を含まないケイ素化合物の強い負帯電性がシリカ表面上で支配的になり、帯電量が少ない正帯電になるか、あるいは、逆に負帯電を示すことになる場合もある。また、Ａ／Ｂ＞２．０の場合は、正帯電シリカが得られるものの、湿度の影響を受けやすくなり、帯電性能の環境安定性が悪くなる。この原因はアミノ基を含有するケイ素化合物のアミノ基がシリカ表面上で支配的になり、親水性が増加（疎水性が低下）するためであると推測される。 In the present invention, regarding A and B, it is necessary to satisfy the relationship of 0.5 ≦ A / B ≦ 2.0. This A / B indicates the ratio of the silicon compound containing an amino group covering silica and the silicon compound not containing an amino group. When A / B <0.5, the silicon compound containing no amino group is strong. In some cases, the negative chargeability becomes dominant on the silica surface, and the charge amount is positive with a small amount of charge, or conversely, negative charge is exhibited. When A / B> 2.0, positively charged silica can be obtained, but it is easily affected by humidity and the environmental stability of charging performance is deteriorated. This is presumably because the amino group of the silicon compound containing an amino group becomes dominant on the silica surface and the hydrophilicity increases (hydrophobicity decreases).
本発明の疎水性正極帯電シリカ微粉末を構成するにあたって使用するシリカは、特に制約されることなく、湿式法、気相法のいずれで製造されたものも使用することができる。ただし、トナー用外添剤に使用すること、および、優れた流動性を確保する観点から、シリカの平均一次粒子径は５〜１００ｎｍであることが好ましい。シリカの平均一次粒子径が５ｎｍより小さいものは、製造自体が困難であり、１００ｎｍより大きいものは、流動性が充分でないからである。ここで、シリカの平均一次粒子径はＢＥＴ比表面積測定値より求めた球相当換算径である。上記平均一次粒子径を求めるためのＢＥＴ比表面積の測定は、窒素ガスの吸着量からＢＥＴ一点法にて比表面積を求めることによって行われる。その際の測定条件は以下の通りである。
測定装置：マルチソーブ１６型（湯浅アイオニクス社製）
脱気温度：１５０℃、脱気時間：２０分、吸着ガス：窒素
The silica used for constituting the hydrophobic positive electrode charged silica fine powder of the present invention is not particularly limited, and those manufactured by either a wet method or a gas phase method can be used. However, the average primary particle diameter of silica is preferably 5 to 100 nm from the viewpoint of use in an external additive for toner and securing excellent fluidity. If the average primary particle diameter of silica is smaller than 5 nm, the production itself is difficult, and if it is larger than 100 nm, the fluidity is not sufficient. Here, the average primary particle diameter of silica is a sphere-equivalent diameter determined from the measured BET specific surface area. The measurement of the BET specific surface area for determining the average primary particle diameter is performed by determining the specific surface area from the adsorption amount of nitrogen gas by the BET single point method. The measurement conditions at that time are as follows.
Measuring device: Multisorb type 16 (manufactured by Yuasa Ionics)
Degassing temperature: 150 ° C., Degassing time: 20 minutes, Adsorbed gas: Nitrogen
そして、本発明の疎水性正帯電シリカ微粉末は、その特性が次の要件を満たしていることが好ましい。つまり、粉体濡れ性試験器におけるメタノール疎水化度分布測定において、７８０ｎｍの波長を有する透過光で測定した透過率（％）が低下し始めたメタノール濃度（％）をＣ（開始点）とし、透過率（％）が最大限低下したメタノール濃度（％）をＤ（終点）とするとき、Ｄ−Ｃの値（ΔＥ）が１≦ΔＥ≦２０となることである。このΔＥは疎水化処理の均一性を示しており、ΔＥが小さいほど、疎水化処理の均一度が高く、この疎水化処理の均一度が高いほど、帯電性能の環境安定性が優れ、また、流動性も高くなる。 And it is preferable that the characteristic of the hydrophobic positively charged silica fine powder of the present invention satisfies the following requirements. That is, in methanol hydrophobization degree distribution measurement in a powder wettability tester, the methanol concentration (%) at which the transmittance (%) measured with transmitted light having a wavelength of 780 nm began to decrease is defined as C (starting point), When the methanol concentration (%) at which the transmittance (%) is reduced to the maximum is D (end point), the DC value (ΔE) is 1 ≦ ΔE ≦ 20. This ΔE indicates the uniformity of the hydrophobization treatment. The smaller the ΔE, the higher the homogeneity of the hydrophobization treatment. The higher the uniformity of the hydrophobization treatment, the better the environmental stability of the charging performance. The fluidity is also increased.
上記メタノール疎水化度分布測定は、粉体濡れ性試験器として「ＷＥＴ−１００Ｐ（レスカ社製）」を用いて、次のように行われる。
まず、２５０ｍｌのトールビーカーに純水７０ｍｌを入れ、測定試料０．０８ｇを水面上に浮かべる。マグネチックスターラーにより３００ｒｐｍで攪拌しながら、定量ポンプでメタノールを２．６ｍｌ／ｍｉｎで滴下し、この溶液の透過率を７８０ｎｍの波長光で測定する。透過率（％）が低下し始めたメタノール濃度（％）Ｃ（開始点）と、透過率（％）が最大限低下したメタノール濃度（％）Ｄ（終点）とを読み取り、そのＤからＣを引くことにより、ΔＥを求める。
The methanol hydrophobization degree distribution measurement is performed as follows using “WET-100P (manufactured by Reska Co.)” as a powder wettability tester.
First, 70 ml of pure water is put into a 250 ml tall beaker, and 0.08 g of a measurement sample is floated on the water surface. While stirring at 300 rpm with a magnetic stirrer, methanol is added dropwise at 2.6 ml / min with a metering pump, and the transmittance of this solution is measured with 780 nm wavelength light. The methanol concentration (%) C (starting point) at which the transmittance (%) began to decrease and the methanol concentration (%) D (end point) at which the transmittance (%) decreased to the maximum were read. By subtracting, ΔE is obtained.
また、本発明の疎水性正帯電シリカ微粉末は、フェライトとの混合における摩擦帯電量（Ｑ）が、＋５０（μＣ／ｇ）≦Ｑ≦＋１０００（μＣ／ｇ）であることが好ましい。
Ｑ＜＋５０の場合には、トナーに適正な帯電量を付与できない場合があり、また、Ｑ＞＋１０００の場合には、トナーの帯電量が高くなりすぎ、トナーの帯電量の制御が難しくなる場合が生じるからである。
In addition, the hydrophobic positively charged silica fine powder of the present invention preferably has a triboelectric charge amount (Q) when mixed with ferrite of +50 (μC / g) ≦ Q ≦ + 1000 (μC / g).
When Q <+50, there is a case where an appropriate charge amount cannot be given to the toner. When Q> +1000, the toner charge amount becomes too high, and it becomes difficult to control the toner charge amount. This is because.
このフェライトとの混合における摩擦帯電量（Ｑ）は、一般にブローオフ帯電量と呼ばれるもので、その測定方法は、後記の実施例の項で説明する。 The triboelectric charge amount (Q) in the mixing with the ferrite is generally called a blow-off charge amount, and the measuring method thereof will be described in the section of the examples described later.
本発明の疎水性正帯電シリカ微粉末は、湿式法、乾式法、いずれでも製造できるが、処理の均一性の点からは、湿式法が好ましい。また、２種のケイ素化合物で疎水化処理する工程において、疎水化処理が湿式法で行われ、かつ、アミノ基を含有するケイ素化合物を先にシリカと接触させ、その後から、アミノ基を含有しないケイ素化合物を接触させる方が、帯電性能の環境安定性を向上させることができるのでより好ましい。この理由は、現在のところ必ずしも明確ではないが、アミノ基を含有するケイ素化合物はシリカに対して反応性が良く、先に接触させた方が疎水化処理の均一性が高まること、および、親水性のアミノ基がシリカ表面の最外層に露出することを防止することができるからではないかと推察される。 The hydrophobic positively charged silica fine powder of the present invention can be produced by either a wet method or a dry method, but the wet method is preferred from the viewpoint of processing uniformity. Further, in the step of hydrophobizing with two kinds of silicon compounds, the hydrophobizing treatment is performed by a wet method, and the silicon compound containing an amino group is first brought into contact with silica, and thereafter no amino group is contained. It is more preferable to contact the silicon compound because the environmental stability of the charging performance can be improved. The reason for this is not necessarily clear at present, but silicon compounds containing amino groups are more reactive with silica, and the first contact with them improves the uniformity of the hydrophobization treatment, and the hydrophilicity. It is presumed that it may be possible to prevent the sex amino group from being exposed to the outermost layer on the silica surface.
本発明の疎水性正帯電シリカ微粉末は、均一な疎水化処理がなされており、温度や湿度などの環境変化に対する安定性が高く、従って、帯電性能の環境安定性が優れている。また、適度な正帯電性能を有し、流動性も優れていて、静電潜像現像用トナーの外添剤として最適なものといえる。 The hydrophobic positively charged silica fine powder of the present invention has been subjected to a uniform hydrophobization treatment, and is highly stable against environmental changes such as temperature and humidity, and therefore has excellent environmental stability of charging performance. In addition, it has moderate positive charging performance and excellent fluidity, and can be said to be an optimal external additive for toner for developing electrostatic latent images.
本発明の疎水性正帯電シリカ微粉末を外添剤として添加する静電潜像現像用トナーは、磁性一成分トナー、非磁性一成分トナー、２成分トナーのいずれでもよく、トナーの構成成分に関しては既知のものを任意に使用することができる。 The electrostatic latent image developing toner to which the hydrophobic positively charged silica fine powder of the present invention is added as an external additive may be any of a magnetic one-component toner, a non-magnetic one-component toner, and a two-component toner. Any known one can be used.
本発明の疎水性正帯電シリカ微粉末の静電潜像現像用トナーへの添加量は、トナー樹脂に対して０．１〜３質量％（トナー樹脂１００質量部に対して疎水性正帯電シリカ微粉末の添加量が０．１〜３質量部）が好ましく、０．２〜２質量％がより好ましい。疎水性正帯電シリカ微粉末の添加量が０．１質量％より少ない場合は、静電潜像現像用トナーの帯電性能の環境安定性の向上効果が充分に得られず、また、３質量％より多い場合は、トナーからの遊離粒子が増加する傾向がある。 The amount of the hydrophobic positively charged silica fine powder of the present invention added to the toner for developing an electrostatic latent image is 0.1 to 3% by mass with respect to the toner resin (the hydrophobic positively charged silica with respect to 100 parts by mass of the toner resin). The addition amount of fine powder is preferably 0.1 to 3 parts by mass, and more preferably 0.2 to 2% by mass. When the amount of the hydrophobic positively charged silica fine powder is less than 0.1% by mass, the effect of improving the environmental stability of the charging performance of the electrostatic latent image developing toner cannot be sufficiently obtained, and 3% by mass. When the amount is larger, free particles from the toner tend to increase.
以下に実施例を挙げて本発明をさらに詳細に説明する。ただし、以下に挙げる実施例は単に例示のために記すものであって、本発明の範囲がこれによって制限されるものではない。 Hereinafter, the present invention will be described in more detail with reference to examples. However, the following examples are described for illustrative purposes only, and the scope of the present invention is not limited thereby.
実施例１
平均一次粒子径１６ｎｍのシリカ（ＢＥＴ比表面積１３０ｍ２／ｇ：日本アエロジル社製＃１３０）１００ｇをトルエン６００ｇに分散し、そのシリカに対し、１４質量％の３−アミノプロピルトリエトキシシラン（アミノ基を含有するケイ素化合物）を添加した後、１５分間分散混合してシリカと接触させ、その後、シリカに対し、１４質量％のトリフルオロプロピルトリメトキシシラン（アミノ基を含有しないケイ素化合物）を添加した後、１５分間分散混合してシリカと接触させた。その分散液を減圧蒸留、乾燥、解砕して、疎水性正帯電シリカ微粉末を得た。この疎水性正帯電シリカ微粉末を製造するにあたって用いたシリカのＢＥＴ比表面積および平均一次粒子径、アミノ基を含有するケイ素化合物の添加量Ａ（質量％）、アミノ基を含有しないケイ素化合物の添加量Ｂ（質量％）、（Ａ＋Ｂ）／Ｓの数値（Ｍ）、Ａ／Ｂの値を後記の表１に示す、ただし、表１には、スペース上の関係で、シリカの「ＢＥＴ比表面積」は単に「比表面積」と簡略化して表示し、また、シリカの「平均一次粒子径」は単に「粒子径」と簡略化して表示し、「アミノ基を含有するケイ素化合物」は「アミノ基含有ケイ素化合物」と簡略化して表示し、「アミノ基を含有しないケイ素化合物」は「アミノ基非含有ケイ素化合物」と簡略化して表示する。また、表１には、以後に示す実施例２〜１０および比較例１〜４のそれらについても示すが、その表示の仕方は実施例１の場合と同様である。
Example 1
100 g of silica having an average primary particle diameter of 16 nm (BET specific surface area 130 m 2 / g: # 130 manufactured by Nippon Aerosil Co., Ltd.) was dispersed in 600 g of toluene, and 14% by mass of 3-aminopropyltriethoxysilane (amino group) with respect to the silica. Was added, dispersed and mixed for 15 minutes and brought into contact with silica, and then 14% by mass of trifluoropropyltrimethoxysilane (silicon compound containing no amino group) was added to the silica. Thereafter, the mixture was dispersed and mixed for 15 minutes and brought into contact with silica. The dispersion was distilled under reduced pressure, dried and crushed to obtain hydrophobic positively charged silica fine powder. BET specific surface area and average primary particle diameter of silica used in producing this hydrophobic positively charged silica fine powder, addition amount A (mass%) of silicon compound containing amino group, addition of silicon compound containing no amino group Amount B (mass%), numerical value of (A + B) / S (M), and A / B values are shown in Table 1 below. However, Table 1 shows the “BET specific surface area of silica in terms of space. "Is simply expressed as" specific surface area "," average primary particle diameter "of silica is simply expressed as" particle diameter ", and" silicon compound containing an amino group "is" amino group " “Silicone compound not containing amino group” is simply expressed as “silicon compound containing no amino group”. Table 1 also shows those of Examples 2 to 10 and Comparative Examples 1 to 4 shown below, and the display method is the same as that of Example 1.
実施例２
実施例１で用いた平均一次粒子径１６ｎｍのシリカに代えて、平均一次粒子径１２ｎｍのシリカ（ＢＥＴ比表面積２００ｍ２／ｇ：日本アエロジル社製＃２００）を用い、３−アミノプロピルトリエトキシシランの添加量を１４質量％から１０質量％に変更し、トリフルオロプロピルトリメトキシシランに代えて、オクチルトリエトキシシランを１０重量％添加した以外は、実施例１と同様の処理を行って疎水性正帯電シリカ微粉末を得た。
Example 2
Instead of silica having an average primary particle diameter of 16 nm used in Example 1, silica having an average primary particle diameter of 12 nm (BET specific surface area 200 m 2 / g: # 200 manufactured by Nippon Aerosil Co., Ltd.) was used, and 3-aminopropyltriethoxysilane was used. Hydrophobicity was obtained by carrying out the same treatment as in Example 1 except that the amount of addition was changed from 14% by mass to 10% by mass and 10% by weight of octyltriethoxysilane was added instead of trifluoropropyltrimethoxysilane. Positively charged silica fine powder was obtained.
実施例３
実施例１におけるトリフルオロプロピルトリメトキシシランに代えて、トリメチルシロキシケイ酸を１４質量％添加した以外は、実施例１と同様の処理を行って疎水性正帯電シリカ微粉末を得た。
Example 3
A hydrophobic positively charged silica fine powder was obtained by performing the same treatment as in Example 1 except that 14% by mass of trimethylsiloxysilicic acid was added instead of trifluoropropyltrimethoxysilane in Example 1.
実施例４
実施例１におけるトリフルオロプロピルトリメトキシシランに代えて、ジメチルポリシロキサンを１４質量％添加した以外は、実施例１と同様の処理を行って疎水性正帯電シリカ微粉末を得た。
Example 4
A hydrophobic positively charged silica fine powder was obtained by performing the same treatment as in Example 1 except that 14% by mass of dimethylpolysiloxane was added instead of trifluoropropyltrimethoxysilane in Example 1.
実施例５
３−アミノプロピルトリエトキシシランの添加量を１４質量％から７質量％に変更し、トリフルオロプロピルトリメトキシシランに代えて、オクチルトリエトキシシランを１４質量％添加した以外は、実施例１と同様の処理を行って疎水性正帯電シリカ微粉末を得た。
Example 5
The amount of 3-aminopropyltriethoxysilane was changed from 14% by mass to 7% by mass, and instead of trifluoropropyltrimethoxysilane, 14% by mass of octyltriethoxysilane was added. Thus, a hydrophobic positively charged silica fine powder was obtained.
実施例６
実施例１におけるトリフルオロプロピルトリメトキシシランに代えて、トリメチルシロキシケイ酸を７質量％添加した以外は、実施例１と同様の処理を行って疎水性正帯電シリカ微粉末を得た。
Example 6
A hydrophobic positively charged silica fine powder was obtained by performing the same treatment as in Example 1 except that 7% by mass of trimethylsiloxysilicic acid was added instead of trifluoropropyltrimethoxysilane in Example 1.
実施例７
３−アミノプロピルトリエトキシシランの添加量を１４質量％から７質量％に変更し、トリフルオロプロピルトリメトキシシランに代えて、ジメチルポリシロキサンを７質量％添加した以外は、実施例１と同様の処理を行って疎水性正帯電シリカ微粉末を得た。
Example 7
The addition amount of 3-aminopropyltriethoxysilane was changed from 14% by mass to 7% by mass, and instead of trifluoropropyltrimethoxysilane, 7% by mass of dimethylpolysiloxane was added. Treatment was carried out to obtain a hydrophobic positively charged silica fine powder.
実施例８
実施例１において用いた平均一次粒子径１６ｎｍのシリカに代えて、平均一次粒子径８０ｎｍのシリカ（ＢＥＴ比表面積４５ｍ２/ｇ：東ソーシリカ社製Ｅ−７４３）を用い、３−アミノプロピルトリエトキシシランの添加量を１４質量％から４質量％に変更し、トリフルオロプロピルトリメトキシシランに代えて、ジメチルポリシロキサンを４質量％添加した以外は、実施例１と同様の処理を行って疎水性正帯電シリカ微粉末を得た。
Example 8
Instead of silica having an average primary particle size of 16 nm used in Example 1, silica having an average primary particle size of 80 nm (BET specific surface area 45 m 2 / g: E-743 manufactured by Tosoh Silica Co., Ltd.) was used, and 3-aminopropyltriethoxy was used. The amount of silane added was changed from 14% by mass to 4% by mass, and instead of trifluoropropyltrimethoxysilane, 4% by mass of dimethylpolysiloxane was added, and the same treatment as in Example 1 was performed to make hydrophobic. Positively charged silica fine powder was obtained.
実施例９
実施例１において用いた平均一次粒子径１６ｎｍのシリカに代えて、平均一次粒子径７ｎｍのシリカ（ＢＥＴ比表面積３００ｍ２/ｇ：日本アエロジル社製＃３００）を用い、３−アミノプロピルトリエトキシシランの添加量を１４質量％から２０重量％に変更し、トリフルオロプロピルトリメトキシシランに代えて、ジメチルポリシロキサンを２０質量％添加した以外は、実施例１と同様の処理を行って疎水性正帯電シリカ微粉末を得た。
Example 9
Instead of silica having an average primary particle diameter of 16 nm used in Example 1, silica having an average primary particle diameter of 7 nm (BET specific surface area 300 m 2 / g: # 300 manufactured by Nippon Aerosil Co., Ltd.) was used, and 3-aminopropyltriethoxysilane was used. In the same manner as in Example 1 except that 20% by mass of dimethylpolysiloxane was added in place of trifluoropropyltrimethoxysilane, the amount of addition of 14% by mass was changed from 14% to 20% by mass. A charged silica fine powder was obtained.
実施例１０
実施例１における３−アミノプロピルトリエトキシシランに代えて、Ｎ−２（アミノエチル）３−アミノプロピルトリメトキシシランを１４質量％添加した以外は、実施例１と同様の処理を行って疎水性正帯電シリカ微粉末を得た。
Example 10
In place of 3-aminopropyltriethoxysilane in Example 1, N-2 (aminoethyl) 3-aminopropyltrimethoxysilane was treated in the same manner as in Example 1 except that 14% by mass was added to make it hydrophobic. Positively charged silica fine powder was obtained.
比較例１
３−アミノプロピルトリエトキシシランの添加量を１４質量％から２０質量％に変更し、トリフルオロプロピルトリメトキシシランの添加量を１４質量％から２０質量％に変更した以外は、実施例１と同様の処理を行った。
Comparative Example 1
The same as Example 1 except that the addition amount of 3-aminopropyltriethoxysilane was changed from 14% by mass to 20% by mass and the addition amount of trifluoropropyltrimethoxysilane was changed from 14% by mass to 20% by mass. Was processed.
比較例２
３−アミノプロピルトリエトキシシランの添加量を１４質量％から５質量％に変更し、トリフルオロプロピルトリメトキシシランに代えて、ジメチルポリシロキサンを５質量％添加した以外は、実施例１と同様の処理を行った。
Comparative Example 2
The addition amount of 3-aminopropyltriethoxysilane was changed from 14% by mass to 5% by mass, and instead of trifluoropropyltrimethoxysilane, 5% by mass of dimethylpolysiloxane was added. Processed.
比較例３
３−アミノプロピルトリエトキシシランの添加量を１４質量％から７質量％に変更し、トリフルオロプロピルトリメトキシシランに代えて、オクチルトリエトキシシランを２１質量％添加とした以外は、実施例１と同様の処理を行った。
Comparative Example 3
Example 1 except that the addition amount of 3-aminopropyltriethoxysilane was changed from 14% by mass to 7% by mass, and 21% by mass of octyltriethoxysilane was added instead of trifluoropropyltrimethoxysilane. The same process was performed.
比較例４
３−アミノプロピルトリエトキシシランの添加量を１４質量％から２１質量％に変更し、トリフルオロプロピルトリメトキシシランに代えて、トリメチルシロキシケイ酸を７質量％添加した以外は、実施例１と同様の処理を行った。
Comparative Example 4
The addition amount of 3-aminopropyltriethoxysilane was changed from 14% by mass to 21% by mass, and instead of trifluoropropyltrimethoxysilane, 7% by mass of trimethylsiloxysilicic acid was added. Was processed.
前記したように、表１に、これらの実施例１〜１０および比較例１〜４において用いたシリカのＢＥＴ比表面積（Ｓ）（表１には「比表面積」で表示）および平均一次粒子径（表１には「粒子径」で表示）、アミノ基を含有するケイ素化合物（表１には「アミノ基含有ケイ素化合物」で表示）の添加量（Ａ）、アミノ基を含有しないケイ素化合物（表１には「アミノ基非含有ケイ素化合物」で表示）の添加量Ｂ、Ｍの値〔（Ａ＋Ｂ）／Ｓの値〕およびＡ／Ｂ値を示す。 As described above, Table 1 shows the BET specific surface area (S) of silica used in Examples 1 to 10 and Comparative Examples 1 to 4 (indicated by “specific surface area” in Table 1) and the average primary particle diameter. (Indicated by “particle size” in Table 1), addition amount (A) of silicon compound containing amino group (indicated by “amino group-containing silicon compound” in Table 1), silicon compound not containing amino group ( Table 1 shows addition amounts B and M (value of (A + B) / S) and A / B value of “amino group-free silicon compound”.
試験例：
上記のようにして得られた実施例１〜１０の疎水性正帯電シリカ微粉末および比較例１〜４のシリカ微粉末について、メタノール疎水化度分布、ブローオフ帯電量、帯電量の環境安定性を調べ、かつそれら実施例１〜１０の疎水性正帯電シリカ微粉末および比較例１〜４のシリカ微粉末を用いて擬似トナーを作製し、その帯電量の環境安定性を調べた。その結果を表２に示す。
Test example:
With respect to the hydrophobic positively charged silica fine powders of Examples 1 to 10 and the silica fine powders of Comparative Examples 1 to 4 obtained as described above, the environmental stability of the methanol hydrophobization degree distribution, the blow-off charge amount, and the charge amount was improved. A pseudo toner was prepared using the hydrophobic positively charged silica fine powders of Examples 1 to 10 and the silica fine powders of Comparative Examples 1 to 4, and the environmental stability of the charge amount was examined. The results are shown in Table 2.
上記メタノール疎水化度分布、ブローオフ帯電量、帯電量の環境安定性の測定方法および擬似トナーの作製方法、その帯電量の環境安定性の測定方法は以下に示す通りである。 The methanol hydrophobization degree distribution, blow-off charge amount, charge amount environmental stability measurement method, pseudo toner preparation method, and charge amount environment stability measurement method are as follows.
メタノール疎水化度分布：
粉体濡れ試験器の「ＷＥＴ−１００Ｐ（レスカ社製）」を用いて、下記の方法でメタノール疎水化度分布を測定した。
Methanol hydrophobicity distribution:
Methanol hydrophobization degree distribution was measured by the following method using “WET-100P (manufactured by Reska Co.)” of a powder wetting tester.
まず、２５０ｍｌのトールビーカーに純水７０ｍｌを入れ、測定試料０．０８ｇを水面上に浮かべる。マグネチックスターラーにより３００ｒｐｍで攪拌しながら、定量ポンプでメタノールを２．６ｍｌ／ｍｉｎで滴下し、この溶液の透過率を７８０ｎｍの波長光で測定し、メタノール疎水化度分布曲線を描写させる。この時、透過率（％）が低下し始めたメタノール濃度（％）Ｃ（開始点）と、透過率（％）が最大限低下したメタノール濃度（％）Ｄ（終点）とを読み取り、それらの結果から、ΔＥ（Ｄ−Ｃの数値）を算出する。 First, 70 ml of pure water is put into a 250 ml tall beaker, and 0.08 g of a measurement sample is floated on the water surface. While stirring at 300 rpm with a magnetic stirrer, methanol is added dropwise at 2.6 ml / min with a metering pump, and the transmittance of this solution is measured with light having a wavelength of 780 nm to draw a methanol hydrophobicity distribution curve. At this time, the methanol concentration (%) C (starting point) at which the transmittance (%) began to decrease and the methanol concentration (%) D (end point) at which the transmittance (%) decreased to the maximum were read. From the result, ΔE (the numerical value of DC) is calculated.
前記したように、このΔＥが小さいほど、疎水化処理の均一度が高く、帯電性能の環境安定性が優れ、また、流動性も高くなる。 As described above, the smaller the ΔE, the higher the uniformity of the hydrophobization treatment, the better the environmental stability of the charging performance, and the higher the fluidity.
ブローオフ帯電量：
ブローオフ粉体帯電量測定装置「ＴＢ−２００（東芝ケミカル社製）」を用いて、下記の方法でブローオフ帯電量〔フェライトとの混合における摩擦帯電量（Ｑ）〕を測定した。
Blow-off charge amount:
Using a blow-off powder charge measuring device “TB-200 (manufactured by Toshiba Chemical Co.)”, the blow-off charge amount [friction charge amount (Q) in mixing with ferrite] was measured by the following method.
測定サンプル０．４ｇとフェライト９６ｇをポリプロピレン製の容器に量り取り、２軸のローター上で１００ｒｐｍの回転速度で１５分間回転させた後、その混合物０．０５ｇを５００メッシュの金網上に量り取り、下記条件でブローオフ帯電量を測定する。
窒素ブロー圧：０．５ｋｇ／ｃｍ２
ブロー時間：２０秒
なお、測定サンプルはそれぞれ３水準の環境下（Ｌ／Ｌ、Ｍ／Ｍ、Ｈ／Ｈ）で１２時間暴露後に測定した。
表２中のＬ／Ｌ、Ｍ／Ｍ、Ｈ／Ｈの温・湿度（相対湿度）はそれぞれ次の通りである。
Ｌ／Ｌ：１０℃、２０％
Ｍ／Ｍ: ２０℃、５０％
Ｈ／Ｈ：３０℃、８０％
0.4 g of a measurement sample and 96 g of ferrite were weighed in a polypropylene container, rotated for 15 minutes at a rotation speed of 100 rpm on a biaxial rotor, and 0.05 g of the mixture was weighed on a 500 mesh wire net, The blow-off charge amount is measured under the following conditions.
Nitrogen blow pressure: 0.5 kg / cm 2
Blow time: 20 seconds
In addition, each measurement sample was measured after exposure for 12 hours in a three-level environment (L / L, M / M, H / H).
The temperature / humidity (relative humidity) of L / L, M / M, and H / H in Table 2 is as follows.
L / L: 10 ° C, 20%
M / M: 20 ° C, 50%
H / H: 30 ° C., 80%
帯電量の環境安定性：
上記Ｌ／Ｌ、Ｍ／Ｍ、Ｈ／Ｈにおけるブローオフ帯電量の測定値から以下の通り算出する。
環境安定性（Ｆ）＝｛（Ｌ／Ｌ−Ｈ／Ｈ）／（Ｍ／Ｍ）｝×１００ （％）
この数値が小さいほど帯電性能の環境安定性が良好といえる。
Environmental stability of charge amount:
It calculates as follows from the measured value of the blow-off charge amount in the L / L, M / M, and H / H.
Environmental stability (F) = {(L / LH / H) / (M / M)} × 100 (%)
The smaller this value, the better the environmental stability of the charging performance.
擬似トナーの作製：
スチレンアクリル系トナー樹脂「ハイマーＳＢ３０５（三洋化成工業社製）」をジェット気流式の粉砕機で粉砕、分級してトナー樹脂を作製した。そのトナー樹脂１００質量部に対し、実施例１〜１０の疎水性正帯電シリカ微粉末および比較例１〜４のシリカ微粉末をそれぞれ別々に１質量％ずつ添加して擬似トナーを作製した。
Preparation of pseudo toner:
A styrene acrylic toner resin “Hymar SB305 (manufactured by Sanyo Chemical Industries)” was pulverized and classified with a jet airflow type pulverizer to prepare a toner resin. A pseudo toner was prepared by separately adding 1% by mass of each of the hydrophobic positively charged silica fine powders of Examples 1 to 10 and the silica fine powder of Comparative Examples 1 to 4 to 100 parts by mass of the toner resin.
この擬似トナーの帯電量の環境安定性（Ｆ’）を前記した実施例１〜１０の疎水性正帯電性シリカ微粉末などの帯電量の環境安定性（Ｆ）と同様の方法により求めた。 The environmental stability (F ′) of the charge amount of the pseudo toner was determined by the same method as the environmental stability (F) of the charge amount of the hydrophobic positively chargeable silica fine powder of Examples 1 to 10 described above.
上記のようにして測定ないし算出したメタノール疎水化度分布、ブローオフ帯電量、帯電量の環境安定性、擬似トナーの帯電量の環境安定性を表２に示すが、表２にはスペース上の関係で、「メタノール疎水化度分布」を簡略化して「疎水化度分布」で表示し、「帯電量の環境安定性」を簡略化して「環境安定性」のみで表示する。 Table 2 shows the methanol hydrophobization degree distribution, blow-off charge amount, charge amount environment stability, and pseudo toner charge amount environment stability measured or calculated as described above. Table 2 shows the spatial relationship. Then, the “methanol hydrophobization degree distribution” is simplified and displayed as “hydrophobic degree distribution”, and “environmental stability of charge amount” is simplified and displayed only as “environmental stability”.
表２に示すように、実施例１〜１０の疎水性正帯電シリカ微粉末は、帯電量の環境安定性（Ｆ）の数値が、比較例１〜４のシリカ微粉末に比べて小さく、帯電性能の環境安定性が優れていることを示していた。 As shown in Table 2, the hydrophobic positively charged silica fine powders of Examples 1 to 10 are smaller in the value of environmental stability (F) of the charge amount than the silica fine powders of Comparative Examples 1 to 4 and charged. It showed that the environmental stability of performance was excellent.
また、実施例１〜１０の疎水性正帯電シリカ微粉末は、表面処理の均一性の指標となるメタノール疎水化度分布測定におけるΔＥの数値でも、比較例１〜４のシリカに比べて小さく、表面処理の均一性が高いことを示していた。一方、擬似トナーを作製した場合においても、実施例１〜１０の疎水性正帯電シリカ微粉末を用いたトナーは、比較例１〜４のシリカ微粉末を用いたトナーに比べて、帯電量の環境安定性（Ｆ’）が小さく、実施例１〜１０の疎水性正帯電シリカ微粉末がトナーにおける帯電性能の環境安定性の向上に寄与することが明らかであった。 Further, the hydrophobic positively charged silica fine powders of Examples 1 to 10 are smaller than the silicas of Comparative Examples 1 to 4 even in the numerical value of ΔE in methanol hydrophobization degree distribution measurement that is an index of surface treatment uniformity. It showed that the uniformity of the surface treatment was high. On the other hand, even when the pseudo toner was prepared, the toner using the hydrophobic positively charged silica fine powder of Examples 1 to 10 had a charge amount higher than that of the toner using the silica fine powder of Comparative Examples 1 to 4. It was clear that the environmental stability (F ′) was small, and the hydrophobic positively charged silica fine powders of Examples 1 to 10 contributed to the improvement of the environmental stability of the charging performance in the toner.
上記のように、本発明の疎水性正帯電シリカ微粉末は、複写機やプリンターなどの複写画像を形成するための静電潜像現像用トナーの外添剤として有用であって、該疎水性正帯電シリカ微粉末を外添剤として添加することにより、流動性が優れ、かつ帯電性能の環境安定性が良好で、鮮鋭性の高い画像が安定して得られる静電潜像現像用トナーを提供することができる。 As described above, the hydrophobic positively-charged silica fine powder of the present invention is useful as an external additive for toner for developing an electrostatic latent image for forming a copy image in a copying machine or a printer, and the hydrophobic By adding positively-charged silica fine powder as an external additive, an electrostatic latent image developing toner that has excellent fluidity, good environmental stability of charging performance, and stable and sharp images can be obtained. Can be provided.
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| JP2008127253A (en) * | 2006-11-22 | 2008-06-05 | Sumitomo Osaka Cement Co Ltd | Surface-treated inorganic oxide particle, method for producing the same, dispersion liquid of the same and resin composition |
| JP5298485B2 (en) * | 2007-09-18 | 2013-09-25 | 富士ゼロックス株式会社 | Electrostatic charge image developer, process cartridge and image forming apparatus |
| JP5470712B2 (en) * | 2008-02-21 | 2014-04-16 | 富士ゼロックス株式会社 | External additive for toner, toner for developing electrostatic image, developer for developing electrostatic image, image forming apparatus, developer cartridge, process cartridge |
| JP5248155B2 (en) * | 2008-03-20 | 2013-07-31 | 株式会社巴川製紙所 | Toner for electrophotography |
| JP5683101B2 (en) * | 2009-08-06 | 2015-03-11 | 株式会社トクヤマ | Surface-treated silica |
| JP5668465B2 (en) * | 2010-12-24 | 2015-02-12 | 日本ゼオン株式会社 | Toner for electrostatic image development |
| JP6382608B2 (en) * | 2014-07-14 | 2018-08-29 | 株式会社トクヤマ | Positively chargeable silica particles and method for producing the same |
| JP6451613B2 (en) * | 2015-12-04 | 2019-01-16 | 京セラドキュメントソリューションズ株式会社 | Positively chargeable toner |
| JP2018054890A (en) * | 2016-09-29 | 2018-04-05 | 京セラドキュメントソリューションズ株式会社 | Positively-charged toner |
| CN115015059A (en) | 2017-05-25 | 2022-09-06 | 信越化学工业株式会社 | Method for analyzing degree of hydrophobization of powder, highly hydrophobized colored pigment, and cosmetic preparation containing same |
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